The present invention refers to a sealing arrangement for the coupling zone between a constant velocity joint and a hub bearing unit of a motor vehicle wheel.
Arrangements are known from patent publications US 2002/0070506 A1 and U.S. Pat. No. 6,354,952 B1 wherein the hub of the wheel receives the driving torque from the bell of the constant velocity joint through a splined coupling. To this end, fixed on the hub is a ring with an axial outer toothing that is inserted in a tubular projection with an inner axial toothing of the outer part or “bell” of the constant velocity joint. The toothed ring and the tubular projection are both provided with a respective circular groove in which an elastic, open locking ring is fitted. This elastic ring has arms at its ends that project through a slot formed at the axially outer end (or outboard end) of the joint bell. Illustrated in FIG. 5 of US 2002/0070506 is a sealing elastic sleeve which, at one end, is positioned on an outer cylindrical surface of the tubular projection of the joint bell, covering from the outside the said slot and the end arms of the locking ring, and at the other end sealingly cooperates with an annular part fixed to the end to the hub, particularly with an insert of a sealing device of the bearing.
A scarcely efficient sealing allows water to penetrate, especially through the slot formed at the end of the joint bell, into the splined interface zone. Rust formed at the interface of the splined coupling renders the disassembling operation of the hub-bearing unit from the constant velocity joint particularly difficult, besides shortening the life of this members.